Corrosion of High-Alloy Materials in Aqueous Hydrofluoric Acid Environments Available to Purchase

A series of immersion tests for eight high-alloy materials was performed in a variety of hydrofluoric acid (HF) environments. Solution strengths of 0.05%, 1%, 10%, 24%, and 48% HF were examined at 24°C, 50°C, and 76°C. Coupons of each alloy were exposed fully immersed in solution and partially exposed in the aerated vapor above each solution. In addition, a limited number of U-bend tests were performed to examine susceptibility to stress corrosion cracking. Comparison of alloy performance (corrosion rate calculated from weight loss, metallographic evaluation of attack) indicated alloys C-22 (UNS N06022) and C-276 (UNS N10276) exhibited overall superior performance. Other alloys showed useful resistance for a limited range of conditions.